Cordless power tools provide many advantages to traditional corded power tools. In particular, cordless tools provide unmatched convenience and portability. An operator can use a cordless power tool anywhere and anytime, regardless of the availability of a power supply. In addition, cordless power tools provide increased safety and reliability because there is no cumbersome cord to maneuver around while working on the job, and no risk of accidently cutting a cord in a hazardous work area.
However, conventional cordless power tools still have their disadvantages. Typically, cordless power tools provide far less power as compared to their corded counterparts. Today, operators desire power tools that provide the same benefits of convenience and portability, while also providing similar performance as corded power tools.
Brushless DC (BLDC) motors have been used in recent years in various cordless power tools. While BLDC motors provide many advantages over universal and permanent magnet DC motors, challenges exist in incorporating BLDC motors into many power tools depending on power requirements and specific applications of tool. The power components needed for driving the BLDC motors in high power applications have conventionally generated too much heat, making BLDC motors unfeasible for high-power power tools. Furthermore, high power applications typically require larger motors. As power tools have become more ergonomically compact, it has become more desireable to reduce the size of the motor while providing the required power output.